难熔金属抗氧化防护技术研究进展

Research Progress on the Oxidation Protection Technology of Refractory Metals

难熔金属及其合金具有高熔点,优异的高温强度和良好的热稳定性,广泛应用于航空航天、武器装备及核工业等领域。但难熔金属抗氧化性差,高温环境下易氧化失效。在难熔金属表面制备抗氧化涂层和基体合金化是提高难熔金属抗氧化性能的有效途径。重点分析了Si、Cr、B、W、Ti、Al等元素在涂层防护方面的抗氧化机理和不同种涂层制备方法对抗氧化性能的影响,探讨了基体合金化如何提高难熔金属的抗氧化性能。合金化元素通过生成氧化层从而发挥钝化作用,提高基体的抗氧化性能。但添加过量会导致合金力学性能恶化,仍需进一步研究在合金化条件下如何平衡力学性能与抗氧化性能。最后,对难熔金属在高温环境下氧化保护的发展方向和趋势进行展望。

Refractory metals and their alloys have high melting points,excellent high-temperature strength,and good thermal stability and are irreplaceable in aerospace,weapons and equipment,the nuclear industry,and high-temperature measurement.However,the oxidation resistance of refractory metals is poor,which easily leads to oxidation failure in a high-temperature environment.The preparation of antioxidation coatings and matrix alloying on the surface of refractory metals are effective ways to improve the oxidation resistance of refractory metals and their alloys.In combination with the systematic research of domestic and foreign scholars on the material composition,element ratio,and preparation methods,the microstructural change,oxidation behavior,and failure mechanism of refractory metals in high-temperature environments were expounded.The antioxidant effects and mechanisms of Si,Cr,B,W,Ti and Al in coating protection were analysed.In addition,the effects of different coating preparation methods on the antioxidant energy were investigated.The mechanism by which matrix alloying can improve the oxidation resistance of refractory metals was subsequently explored.Among them,a layer of oxide is formed after the oxidation of alloying elements to play a passivation role and improve the oxidation resistance of the matrix,but excessive addition leads to deterioration of the mechanical properties of the alloy,and further research is still needed on how to balance the mechanical properties and oxidation resistance under alloying conditions.Finally,the development direction and trend of oxidation protection of refractory metals in high-temperature environments are proposed.